BATON ROUGE - U.S. Sen. Mary Landrieu and her main Republican challenger, Congressman Bill Cassidy, traded jabs over leadership and effectiveness as they signed up for the November election.

Qualifying for the Nov. 4 ballot opened Wednesday and continues through Friday.

Landrieu, a Democrat, talked of her 18 years of seniority, saying Louisiana voters shouldn't relinquish that clout.

Cassidy described his campaign as crucial to returning the U.S. Senate to GOP control.

Republicans showed up with "Air Mary" signs, a dig at Landrieu for billing private chartered planes to her Senate office when she used the flights to attend campaign fundraisers.

Three incumbent congressmen also signed up for re-election: Democrat Cedric Richmond and Republicans Charles Boustany and John Fleming. Former Gov. Edwin Edwards officially registered to run for the 6th District congressional seat.